The present invention relates to a homogeneous bulky porous ceramic material, having adjustable and controlled porosity and pore diameter. The present ceramic porous body can be used for liquid filtration, gas separation, or for bringing fluids into contact as in catalytic reactions, or for emulsion production and other applications that use a ceramic porous material.
Numerous ceramic membranes are already known. They are generally formed by successively stacking layers on a support having large pores (macroporous support). The support gives the membrane its necessary mechanical strength. The stack of layers makes it possible to progressively reduce pore diameter. These layers are difficult to develop. The main characteristics of the filtration layer, in other words pore diameter and porosity (or porous volume), are also for a large part a function of the characteristics of the layer on which they are deposited, and this does not allow variation over a very extensive range. Additionally, their firing temperature needs to be below the firing temperature of the sub-layer. In some cases, this means a low firing temperature that is insufficient to allow optimal keying or bonding of the layer onto the sub-layer.
With this technique, filtration membrane manufacture is a long and costly procedure including a large number of steps; it does not make it possible to adapt membrane characteristics to the fluids to be filtered. On the other hand, porosity of the macroporous support is low to ensure sufficient mechanical strength when the membrane is in use. Finally, provision of a small-pore-diameter layer requires fairly low firing temperatures, such temperatures being insufficient to obtain the optimal properties for the material.